Description of problem: a .xlsx named as a .xls will fail to open
libreoffice-3.6.5.2-2.fc18 has been submitted as an update for Fedora 18. https://admin.fedoraproject.org/updates/libreoffice-3.6.5.2-2.fc18
Package libreoffice-3.6.5.2-2.fc18: * should fix your issue, * was pushed to the Fedora 18 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing libreoffice-3.6.5.2-2.fc18' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2013-2042/libreoffice-3.6.5.2-2.fc18 then log in and leave karma (feedback).
libreoffice-3.6.5.2-2.fc18 has been pushed to the Fedora 18 stable repository. If problems still persist, please make note of it in this bug report.